From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS4713 221.184.0.0/13 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by dcvr.yhbt.net (Postfix) with ESMTP id E6A0A1F463 for ; Tue, 3 Dec 2019 23:45:40 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id B2429120AF6; Wed, 4 Dec 2019 08:45:29 +0900 (JST) Received: from o1678948x4.outbound-mail.sendgrid.net (o1678948x4.outbound-mail.sendgrid.net [167.89.48.4]) by neon.ruby-lang.org (Postfix) with ESMTPS id 79AEE120ADF for ; Wed, 4 Dec 2019 08:45:27 +0900 (JST) Received: by filter0090p3mdw1.sendgrid.net with SMTP id filter0090p3mdw1-20332-5DE6F398-11 2019-12-03 23:45:28.774544335 +0000 UTC m=+1209226.683668214 Received: from herokuapp.com (unknown [3.93.59.70]) by ismtpd0055p1iad2.sendgrid.net (SG) with ESMTP id RuKzQpYMQ7KpfpIZcI2-Yg for ; Tue, 03 Dec 2019 23:45:28.710 +0000 (UTC) Date: Tue, 03 Dec 2019 23:45:28 +0000 (UTC) From: merch-redmine@jeremyevans.net Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 71734 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 14183 X-Redmine-Issue-Author: mame X-Redmine-Sender: jeremyevans0 X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-SG-EID: =?us-ascii?Q?RVE3t853K5scBhbmJHUzZTFFeVC=2FZSUmHZ0Dc+26wcEi2CTgsF1oz0wTSSxGGN?= =?us-ascii?Q?BIjB3E1u1GVaznpB9Ze5sHlfuQSVt4xfqrgIRW4?= =?us-ascii?Q?0RrbOTnMizUmdAplGhzWFOYs=2FQY0QactrI8vk7B?= =?us-ascii?Q?3R+ACGQ11jeT4+vEvFQ9pATR9kqGIMt+V0uSkpI?= =?us-ascii?Q?+v=2FPzEVHu+IUihjQF65fAOFygpKvBWom7GQ=3D=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 96092 Subject: [ruby-core:96092] [Ruby master Feature#14183] "Real" keyword argument X-BeenThere: ruby-core@ruby-lang.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: Ruby developers List-Id: Ruby developers List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #14183 has been updated by jeremyevans0 (Jeremy Evans). Shortly after the release of 2.7.0, I would like to merge the branch at https://github.com/jeremyevans/ruby/tree/r3, which fully separates positional and keyword arguments. I've been maintaining this branch for a couple months now and using it for testing. I rebased this branch against today's master, and will try to rebase it weekly for the next few weeks. ---------------------------------------- Feature #14183: "Real" keyword argument https://bugs.ruby-lang.org/issues/14183#change-82950 * Author: mame (Yusuke Endoh) * Status: Closed * Priority: Normal * Assignee: * Target version: Next Major ---------------------------------------- In RubyWorld Conference 2017 and RubyConf 2017, Matz officially said that Ruby 3.0 will have "real" keyword arguments. AFAIK there is no ticket about it, so I'm creating this (based on my understanding). In Ruby 2, the keyword argument is a normal argument that is a Hash object (whose keys are all symbols) and is passed as the last argument. This design is chosen because of compatibility, but it is fairly complex, and has been a source of many corner cases where the behavior is not intuitive. (Some related tickets: #8040, #8316, #9898, #10856, #11236, #11967, #12104, #12717, #12821, #13336, #13647, #14130) In Ruby 3, a keyword argument will be completely separated from normal arguments. (Like a block parameter that is also completely separated from normal arguments.) This change will break compatibility; if you want to pass or accept keyword argument, you always need to use bare `sym: val` or double-splat `**` syntax: ``` # The following calls pass keyword arguments foo(..., key: val) foo(..., **hsh) foo(..., key: val, **hsh) # The following calls pass **normal** arguments foo(..., {key: val}) foo(..., hsh) foo(..., {key: val, **hsh}) # The following method definitions accept keyword argument def foo(..., key: val) end def foo(..., **hsh) end # The following method definitions accept **normal** argument def foo(..., hsh) end ``` In other words, the following programs WILL NOT work: ``` # This will cause an ArgumentError because the method foo does not accept keyword argument def foo(a, b, c, hsh) p hsh[:key] end foo(1, 2, 3, key: 42) # The following will work; you need to use keyword rest operator explicitly def foo(a, b, c, **hsh) p hsh[:key] end foo(1, 2, 3, key: 42) # This will cause an ArgumentError because the method call does not pass keyword argument def foo(a, b, c, key: 1) end h = {key: 42} foo(1, 2, 3, h) # The following will work; you need to use keyword rest operator explicitly def foo(a, b, c, key: 1) end h = {key: 42} foo(1, 2, 3, **h) ``` I think here is a transition path: * Ruby 2.6 (or 2.7?) will output a warning when a normal argument is interpreted as keyword argument, or vice versa. * Ruby 3.0 will use the new semantics. ---Files-------------------------------- vm_args.diff (4.19 KB) vm_args_v2.diff (4.18 KB) -- https://bugs.ruby-lang.org/